Petri dish including locking means for forming a stack

ABSTRACT

A Petri dish has members including a receptacle and an additional lid, both having an axisymmetric shape and which are delimited by a bottom wall and at least one peripheral wall, the receptacle and lid bearing complementary lock sections so that when a stack is formed by superposing at least two dishes, borne by a first component of a first dish which can engage with the lock section of the second component of the second dish, thus making them rigidly connected to one another. These lock sections cooperate by relative rotational movement of one dish with respect to the other, the lock sections being borne by the peripheral walls and including protrusions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase Entry of International ApplicationNo. PCT/EP2011/058452, filed on May 24, 2011, which claims priority toFrench Patent Application Serial No. 1054959, filed on Jun. 22, 2010,both of which are incorporated by reference herein.

BACKGROUND AND SUMMARY

The present invention relates to a Petri dish for cultivatingmicro-organisms, which consists of two members, i.e. a receptacle and anadditional lid and which both have a revolution shape.

Such Petri dishes are widely used notably in laboratories and thesedishes are provided in order to be superposed so as to form stacks. Thisnotably allows the operators to form different batches of Petri dishes,for example so as to sort them out according to the nature of theculture which is made therein. Documents JP-2003 047459, JP-2003 102463,US-2002/045245 and U.S. Pat. No. 4,160,700 illustrate the state of theart in this matter. However, if this dish stacking function is possible,to this day, there does not exist any means which allows retention ofthe dishes attached to each other.

Also, up to now, the handling of culture dishes requires the use oftransport containers and of external systems for attaching the dishestogether. Thus, it is common that the users make use of an elastic or ofadhesive tape for securing the dishes together. It is understood thatthe use of external means involves control of their sanitary quality,and therefore of their sterilization. In certain cases, theseconstraints for handling and transporting Petri dishes are solved byusing an additional disposable transport tool, thereby allowing thedisplacement of a batch of dishes from one place to another, which inall the scenarios involves an additional cost.

The present invention has the object of solving these difficulties. Forthis purpose, it proposes a Petri dish which consists of two members,i.e. a receptacle and an additional lid, which both have anaxisymmetrical shape (revolution shape) and which are each delimited bya bottom wall and at least one peripheral wall, that said receptacle andlid bearing additional locking means laid out so that, upon forming astack formed with the superposition of at least two dishes, the lockingmeans borne by a first member of a first dish may cooperate with lockingmeans of the second member of the second dish, making them thusinterdependent on each other, one of said members including a peripheralwall which extends above and below the bottom wall, while the other oneis dimensioned so that, upon forming said stack, said member of a firstdish is partly engaged into the other member of a second dish, in ahousing delimited by the bottom wall and a portion of said wall,characterized by the fact that said additional locking means are able tocooperate by a relative rotary movement of one dish relatively to theother, that said locking means are borne by the peripheral walls andthat they consist in protrusions. Thus, according to the invention, themembers which make up each of the Petri dishes integrate withinthemselves means for locking to another dish. By their presence, it istherefore possible to form stacks of dishes, in which each dish is madeinterdependent on its neighbor(s) so as to form an assembly which may behandled without any other external connection means.

According to advantageous and non-limiting characteristics of this dish:

-   -   said protrusions are at least two in number, are angularly        equidistant and extend over an angular fraction of said wall;    -   said protrusions have the shape of portions of mating        (complementary) helicoidal ribs;    -   the bottom wall of one of said members bulges outwards and is        elastically deformable so that it occupies a substantially        planar position. Other characteristics and advantages of the        present invention will become apparent upon reading the detailed        description which follows, of a preferential embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

This description will be made with reference to the appended drawingswherein:

FIG. 1 is a very schematic view, according to a diametrical sectionalview, of a Petri dish structure according to the invention;

FIG. 2 is a side view of the lid of such a Petri dish, while FIG. 3 isan enlarged view of the area marked by a circle in the previous figure;

FIG. 4 is a top view of the lid of FIG. 4, while FIG. 5 is an enlargedview of the area marked with a circle in the previous figure;

FIG. 6 is a bottom view of a receptacle of a Petri dish according to theinvention, while FIG. 7 is an enlarged view of the area marked by acircle in the previous figure;

FIG. 8 is a perspective view of the receptacle of FIG. 6 while FIG. 9 isan enlarged view of the area marked by a circle in the previous figure;

FIGS. 10, 12, 15 and 18 are cross-sectional views of the receptacle of adish B₁ and of the lid of a dish B₂, in different positions whichfinally lead to their being interdependent on each other; and

FIGS. 11, 13, 14, 16, 17 and 19 are detailed views of the areas markedby a circle in the figures located just above.

DETAILED DESCRIPTION

The present invention most particularly applies to a Petri dish such asthe one which is very schematically illustrated in FIG. 1. Like allPetri dishes, the latter consists of two members, i.e. a receptacle 2and an additional lid 3 and both have a revolution shape. They are forexample made in transparent plastic material such as crystallinepolystyrene.

The receptacle 2 includes a generally planar bottom wall 20 which issurrounded by a peripheral wall 21. As shown in this figure, this wallextends both above and below the plane in which the bottom wall 20 iscontained, in order to form an upper wall portion 210 and a lower wallportion 211. In the embodiment shown, the bottom wall 20 also includesanother wall 22, a so called “inner wall”, so that there exists anannular space between both aforementioned coaxial walls. The bottom wall20 delimits with the inner wall 22 the space in which a culture mediumis deposited.

The lid 3 consists of a bottom wall 30 and of a peripheral wall 31. Thelatter is dimensioned so as to be able to be positioned against thebottom wall 20 of the receptacle 2, between the walls 21 and 22. Thesereceptacle 2 and lid 3 may include means not shown which allow them tobe immobilized relatively to each other.

Under the letter L is referenced in this figure, an open housing whichis delimited by the bottom wall 20 of the receptacle and the lowerportion 211 of the wall 20. This housing has a diameter D. The lid 3 isas for it dimensioned so as to have a diameter d such that this lid maybe inserted into the annular space located between the walls 21 and 22,as already mentioned, but in such a way that the lid of anotheridentical dish may be inserted into the aforementioned housing L.

This is the situation shown in FIG. 1 wherein the lid of the second dishis illustrated as a profile in dashed lines. This dish configuration isa traditional configuration. However, in certain embodiments not shownthe structure of the receptacle 2 and of the lid 3 may be inverted. Inother words, by flipping FIG. 1 by 180°, the lid referenced as 3 wouldbe formed by the receptacle 2 and vice versa.

In the embodiment of FIGS. 2 and the following figures, the lid 3 has onits peripheral wall 31, protrusions or nipples referenced as 4. One isdealing here with a lid which includes three identical and angularlyequidistant protrusions 4, as this is well visible in FIG. 4. Theseprotrusions extend radially outwards while originating on the externalface of the wall 31. They have two upper and lower faces 41 parallel andtilted by an acute angle a relatively to the horizontal. Both of theirvertical lateral faces are referenced as 40, and their end face as 42.

Now referring to FIGS. 6 to 9, it is seen that the receptacle 2 alsoincludes the same number of additional radial protrusions 5, which areborne by the lower portion 211 of the wall 2 and turned towards theinside of the dish. Seen from the front, these protrusions assume anL-shape, with a base 51, the upper face 510 of which is extendingupwards, and with a vertical branch 52, the face 520 of which forms anabutment. The transverse extension of these protrusions is provided sothat, if a receptacle 2 and a lid 3 are superposed, the additionalprotrusions 4 and 5 interfere when they are brought closer to eachother. In some way, the protrusions 4 and 5 which have just been shown,have the shape of a portion of complementary helicoidal ribs.

In FIGS. 10 and 12, the receptacle 2 of a first Petri dish B₁ as well asthe lid 3 of a second Petri dish B₂ are illustrated. These figures showthe relative positions of both of these members, when it is desired tomake them interdependent on each other. Of course, in practice, thereceptacle 2 of the dish B₁ is covered with its lid 3, while the lid 3of the dish B₂ is assembled to its receptacle 2. The latter however hasnot been illustrated in the figures in order not to unnecessarily burdenthem.

It will be noted, with reference to FIG. 10, that the bottom wall 30 ofthe lid 3 slightly bulges, with a convexity turned towards the outsideof said lid, this bottom wall having the capability of being elasticallydeformable when pressure is exerted on said wall. In other words,subject to such pressure, it has the capability of being brought backinto a position where it is substantially planar. It should be notedthat in FIG. 10 and the following figures, the protrusions 4 which equipthe lid 3 are seen in transparency, which explains that they have aninverted orientation with respect to that of FIGS. 2 and 3, in whichthey are seen from the outside of said lid.

With reference to FIGS. 10 and 11 and with view to forming a stack ofdishes, two dishes B₁and B₂ are brought closer together so that the lid3 of the lower dish B₂ partly enters the housing L of the receptacle 2of the upper dish B₁ and the protrusions 4 and 5 do not coincidevertically (in other words they are not found vertically below eachother). This is illustrated in FIG. 10. This closing-in movementcontinues until the bottom wall 30 of the lid 3 abuts against the bottomwall 20 of the receptacle 2. In this position, the lid 2 has a ratedheight e₁ and which corresponds to the cumulated height of the wall 31and of the bottom wall 30, because of its slightly curved shape.

Referring to FIGS. 13 and 14, it is then seen that the face 510 of theprotrusion 5 is at a slightly upper level than that of the lower face 41of the protrusion 4 so that even if a rotary movement is imparted to oneof the dishes, relatively to each other, said protrusions cannotcooperate but on the contrary will abut against each other. On the otherhand, and as illustrated in FIG. 15 by applying pressure on the upperdish B₁, the deformation of the bottom wall 30 of the lid 3 is made sothat the latter from now on occupies a rated height e₂ of less than theheight e₁. By doing this, said faces 510 and 41 are at the same level,so that by a rotary movement of a dish relatively to the other, it ispossible to engage the protrusion 4 into the protrusion 5.

The tilted orientation of the faces 41 and 510, in the fashion ofportions of helicoidal ribs, facilitates this engagement. Of course, oneskilled in the art will be able to adapt the dimensions and therelatively positions of the protrusions 4 and 5 so that they cooperateintimately.

Finally, the situation of FIG. 18 is then attained in which bothprotrusions are engaged into each other. It will be noted that thevertical branch of the protrusion 5 forms an abutment which prevents anycontinuation of the rotary movement of one dish relatively to the other,so that the protrusions are locked in this condition. By exertingtraction on one dish relatively to the other, in a direction generallyperpendicular to their bottom wall, it is absolutely impossible todetach them from each other. Such a detachment can only be appliedvoluntarily, by performing a rotary movement in the opposite directionto the one which was performed earlier. By making use of the meansdescribed above, it is therefore possible to form stacks of Petri disheswhich are made interdependent on each other, two by two, so that it ispossible to envision the lifting of such a stack simply by grasping theupper dish of the stack.

Of course, the present invention applies to all the structures of Petridishes which include additional locking means borne by the membersformed by the receptacle and the lid. In the example described above,the lower portion 211 of the wall 21 of the receptacle 2 is intended tobe continuous. However, nothing prevents certain areas from havingdiscontinuities notably in order to lighten said Petri dish at the most.

The invention claimed is:
 1. A Petri dish comprising members including areceptacle and a lid, both of which have a cylindrical shape and whichare delimited by a bottom wall and at least one peripheral wall, each ofsaid receptacle and said lid including a lock section laid out so that,upon forming a stack formed with superposition of at least two of saidPetri dishes, said lock section borne by a first of said members of afirst of said Petri dishes cooperate with said lock section of a secondof said members of a second of said Petri dishes, making said firstmember of said first Petri dish and said second member of said secondPetri dish thus interdependent on each other, said peripheral wall ofsaid second member extending above and below said bottom wall while saidfirst member is dimensioned so that, upon forming said stack, said firstmember of said first Petri dish is partly engaged into said secondmember of said second Petri dish, in a housing delimited by said bottomwall and a portion of said peripheral wall, said lock sectionscooperating by a rotational movement of one of said Petri dishesrelative to the other one, and said lock sections being borne by saidperipheral walls of said receptacle and said lid and includingprotrusions.
 2. The dish according to claim 1, wherein said protrusionsare at least two in number, are angularly equidistant and extend over anangular fraction of said peripheral walls.
 3. The dish according toclaim 1, wherein that said protrusions have shapes of portions of matinghelicoidal ribs.
 4. The dish according to claim 1, wherein said bottomwall of one of said members bulges outwards and is elasticallydeformable so that it occupies a substantially planar position.
 5. Thedish according to claim 4, wherein when pressure is applied to one ofsaid Petri dishes, said bottom wall of the one of said memberselastically deforms to position said lock sections relative to oneanother such that one of said Petri dishes is rotatable relative to theother one of said Petri dishes to engage said lock sections with oneanother.
 6. The dish according to claim 1, wherein said protrusionsinclude a first protrusion extending radially outward from saidperipheral wall of said lid, and a second protrusion extending radiallyinward from said peripheral wall of said receptacle.
 7. The dishaccording to claim 1, wherein at least one of said protrusions includesa vertical branch that acts as a stop when the other one of saidprotrusions abuts said vertical branch, thereby preventing furtherrotational movement of one of said Petri dishes relative to the otherone.
 8. A Petri dish comprising: a receptacle including a bottom wall, aperipheral wall, and a protrusion extending from the at least peripheralwall; and a lid configured to cover at least a portion of the receptacleto define an enclosed space, the lid including a bottom wall, aperipheral wall, and a protrusion extending from the peripheral wall ofthe lid, wherein when a first of said Petri dish is stacked on top of asecond of said Petri dish such that said receptacle of said first Petridish is on top of said lid of said second Petri dish, one of saidreceptacle of said first Petri dish and said lid of said second Petridish is rotatable relative to the other one of said receptacle of saidfirst Petri dish and said lid of said second Petri dish to engage saidprotrusions with one another and thereby prevent detaching said Petridishes from one another by exerting a force on one of said Petri dishesrelative to the other one of said Petri dishes in a directionperpendicular to said bottom walls of said Petri dishes.
 9. The dishaccording to claim 8, wherein said protrusion on said lid extendsradially outward from said peripheral wall of said lid, and saidprotrusion on said receptacle extends radially inward from saidperipheral wall of said receptacle.
 10. The dish according to claim 8,wherein at least one of said protrusions includes a vertical branch thatacts as a stop when the other one of said protrusions abuts saidvertical branch, thereby preventing further rotational movement of theone of said receptacle of said first Petri dish and said lid of saidsecond Petri dish relative to the other one of said receptacle of saidfirst Petri dish and said lid of said second Petri dish.
 11. The dishaccording to claim 8, wherein said peripheral wall of said receptacleextends above and below said bottom wall of said receptacle, and saidreceptacle further includes an inner wall that cooperates with theperipheral wall of said receptacle to define an annular space locatedtherebetween.
 12. The dish according to claim 11, wherein said lid isdimensioned so that said peripheral wall of said lid is insertable intothe annular space located between said peripheral wall of saidreceptacle and said inner wall of said receptacle.
 13. The dishaccording to claim 8, wherein said bottom wall of said lid bulgesoutwards and is elastically deformable so that it occupies asubstantially planar position.
 14. The dish according to claim 13,wherein when downward pressure is applied to said first Petri dish, saidbottom wall of said lid of said second Petri dish elastically deforms toposition at least part of said protrusion on said receptacle of saidfirst Petri dish below said protrusion on said lid of said second Petridish such that one of said receptacle of said first Petri dish and saidlid of said second Petri dish is rotatable relative to the other one ofsaid receptacle of said first Petri dish and said lid of said secondPetri dish to engage said protrusions with one another.